SYNCHRO -SETTE
THE SUBSCRIPTION MAGAZINE RM HU MICROCOMPUTER
TIMEX - SINCLAIR
THIS MCNTH’S PROGRAMS 2
EDITOR RAMBLINGS 6
THE COMPUTER TUTOR - simulating DRAW & CIRCLE 9
LETTERS TO THE EDITOR 11 .
TS-2068 SCREEN MEMORY MAP 13
DRAWING ELLIPSOIDS ON THE TS-2068 15
VOLUME 3 ~ NUMBER 3 - MARCH 1984 - CASSETTE' ISSUE - $10.00
SYCHRO - SETTE IS PUBLISHED MONTHLY BY : THE S & S COMPANY
HI W. LAKE ST. APPISOH ILL A01P1 (3121 «»-«»»
fhis Month's Programs
Ti,ere are 7 programs on
this month's cassette, not
counting the LOADER program.
The program names are as
they appear on the above menu,
which is similar to what will
appear on the screen when the
LOADER program is running.
Each program is recorded
only once on each side of the
cassette. The first programs
that can be LOADed will be of
the small size followed by the
larger sized programs. The
other side of the cassette is
a duplicate of the first
side.
Feu: you new subscribers who
aren't familiar with IOADing
procedures for cassette
programs , follow these
directions :
A - Make sure that the volume
setting of the recorder is set
at about 80 % maximum.
B - If you have a Bass and/or
Treble control on the
recorder, make sure the Treble
is at maximum and the Bass is
at minimun.
C - To LOAD the first program,
type in LOAD "" and press the
ENTER key on the computer.
Then press the PLAY button of
the recorder. The lead time on
the NOV/83 cassette is about
10 seconds until the first
program begins.
The time needed to load the
LOADER program is 48 seconds.
When the program is loaded, a
list of this month's programs
will appear automatically.
Shut off the recorder when
the LOADER program is loaded.
Any of the listed programs can
new be loaded into the
computer by pressing the
appropriate number on the
keyboard and then pressing the
PLAY key on the recorder. The
ly&L v . tflO
loader program loads by
searching for the name of the
program you want and ignoring
any of the other programs it
may encounter along the way.
If you want to go directly
to a program without waiting,
we suggest you first find the
tape location of the beginning
of each of the programs with
your recorder counter . This
can be done as you go through
the programs the first time,
noting the tape location on
the counter as each one is
being loaded.
If you don't have a
counter, approximate the tape
position with the fast forward
key just before where the
program would start, and then
LOAD the program with the name
of the program using the
format IOAD "NAME CF
PROGRAM” .
Sane of our subscribers
have told us that they could
not get the programs to load
by name but they would load
with the double quotes. Others
have told us that the loader
program wouldn't load certain
programs. Most have told us
that all the programs could be
loaded either way. Every
custaner's cassette is made
fran the same master tape, so
the programs on everyone's
cassettes are identical . We
feel it is most probably a
problem of volume adjustment
or recorder design. We have
noticed this situation on sane
of our recorders.
PROGRAMS (all programs this
month are self -running
- program's name has inverse
last character if
self -running
RT = run time/HT * load time)
There is an approximate 7 to
20 second pause between
programs
NOTE! These programs, with
minor modification , can be
typed into the TS-2068 .
SCROLL, FAST & SLOW would be
eliminated and CODES and
numbers following CHR$ would
have to be changed as would
any numbers following USR,
POKE, PEEK, PLOT or UNPLOT.
3<£-j'Y
"BCMB-CATCHER" LT = s 53
The "5" and "8" arrow keys
control the movement of a
pillow in this game that you
manuever to catch bombs that
are falling.
fS--? Y
"LAND-MINE" LT = 1:14
In this game, you try to
travel through a minefield
without hitting a land mine.
The game starts with the
minefield shown an the screen.
There is a delay as the
computer hides the mines under
the appropriate co-ordinates.
3
The computer will then ask you
how many co-ordinates you want
to move. You will be awarded
either positive or negative
points each time you advance
and your position will be
marked. If you land on a land
mine, you will be sent back to
the beginning to start over.
The game is over when you
reach the end and your score
will be determined by the
amount of moves versus your
total points.
■3&- t l /J
" SLOT-MACHINE " LT = 2:51
Our thanks to Rick Blewitt
and his father John for this
program. It simulates the play
of a one-armed bandit where
the user plays with a certain
amount of nickels. You tell
the canputer how many and then
sit back.
There was no documentation
regarding rules but it does
give a lot of play for the
money along with good
"BOWLING" LT = 1:31
Although not a full-blown
bowling average program, it
can be used as a base to
include a whole league. It is
designed to keep averages ,
high game and high series for
one team.
Start the program with
prompt #1 and enter requested
data for how many weeks in the
season, hew many players and
the players' names.
Prompt #2 allows entry of
scores cn a week by week
basis. Prompt #3 can have the
data displayed and pranpt #4
will allcw players' names or
scores to be edited. Pranpt #5
allows the data to be saved on
tape with a file name.
VC,L tf/o i >r-3<5j
"MINICALC" LT = 1:30
Here is a mini -vers ion of
the Vis i -Calc type programs.
The program starts with a 3 by
7 grid with a blinking cursor
at the i_pper left box. The
cursor can be moved with the
shift/arrow keys to any box.
The "B" key brings it to the
first box and the "N" key to
the last box . The other
cartnands are as follcws:
"V" - allows entry of a
numeric value
"F" - allows entry of a
formula
"D" - displays the formula in
the cursor box
"C" - calculates the formula
in the cursor box
A simple example for use of
this program might be for a
simple payroll application .
Let us say that we have 2
employees, one makes $4.51 per
hour and the other $5.25 per
hour. With the cursor in box
4
A1 press the "V" key. New
enter "4.51" and press enter,
move the cursor to box A2,
press the "V" key again and
enter "5.25". Now move the
cursor to the A3 box and using
the same value format, alter
"40" for 40 hours worked for
each employee. Now go to box
A4 and press the "F" key. We
want to multiply the hourly
wage in box Al times the hours
worked in box A3 so enter
"A1*A3".
The box will now contain a
graphic "F" in it. If we ever
want to check the formula in
this box, we need only move
the cursor to it and press the
"D" key and the formula will
be dispayed at the bottom of
the screen until we press any
key but BREAK (try it now).
New position the cursor in
box A5 and enter the formula
"A2*A3" the same way.
You may new calculate
either of the formulae by
putting the cursor in the
appropriate box and pressing
the "C" key. The box will then
display the appropriate sum
until any key (except BREAK)
is pressed . Formulae can
contain the logical operators
<+>, <->, <*>, </> and <**>
and be up to 32 characters
long. They can be longer but
an error will occur if you
want to display them.
Even though this program is
limited to only 21 boxes and
does not have duplication and
replication or print-out
features (add a COPY caimand
with appropriate input for
print -out), it is extremely
powerful and easy to use and
would make an excellent base
for a more sophisticated
—version.
* vatr
2-Z^->-S<Z
"BULLETIN"
Our bi-monthly bulletin
board program. Pressing "P"
pauses the scroll. Pressing
any key restarts it. Pressing
H B" makes it move backraxds
and "F 11 makes it go f award.
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5
TIME-STAR COMPUTERS
Details are sketchy at this
time but there is a company
that is planning to acquire
merchandising rights to the
Timex 1500 and 2068 computers.
In a conversation with David
Higgenbottan of Trinity Magnum
Co. in California, a bold plan
to sell these computers aider
the TIME-STAR name through a
nation-wide chain of new
stores . Called "THE LITTLE
COMPUTER STORE", a franchise
system is being developed.
After - mar ket software and
hardware companies are also
being contacted regarding
their products. The customer
could enter the store and
purchase both hardware and
software on the spot. Over 48
companies so far have
expressed interest.
These stores might also
sell other in-expensive micros
with related software and
hardware . One of the big
attractions would be that
software duplication would be
done on location and that
consumers could examine
programs on the computer
before purchase .
Mr. Higgenbottan sees the
effort as a metamorphisis for
the Timex market with in-roads
to be developed in educational
institutions .
We wish him luck and
success and will help in any
way we can. For further
information , contact Mr .
Higgenbottan at (1-213)
864-7068 .
CONVERSION PROBLEMS
People have been contacting
us regarding problems with the
software programs designed to
convert TS-1000 programs to
TS-2068 programs. Without
mentioning manufacturing
names, the ones mentioned to
us would oily give partial
success.
We experienced problems
with the ones we used also
except with one, and certain
rules had to be followed to
the letter.
The one we had the best
lixk with was the one
published in SYNTAX (Dec/83
issue - 1-617/456-3661 RD 2,
6
BOX 457, HARVARD, MA, 01451)
called FIRSTLOADER which is
also available on tape for
$19.95 from E-Z Key, Suite
75-stx 711 Southern Artery,
Quincy, MA, 1-617/773-1187.
When using this or any of
the 1000/2068 conversion
programs , I cannot stress
enough the importance of
adhering to the following
guidelines .
- Make sure the 1000 tape has
been prepared as clean and
free of noise pulses as
possible. Disconnect the EAR
plug when making the 1000
copy. Ruining the recorder on
batteries rather than A/C
helps. Purchased software from
vendors is usually noise free
and copies don't have to be
made.
- Once the conversion program
is in the 2068, advance the
1000 program in the recorder
to the segment just before the
program starts . This segment
usually lasts for about 5
seconds and should be
completely noise free. Listen
to it with the cords
disconnected. If there is
noise in this portion, there
most probably will be noise
thoughout the program. The
conversion program will
identify these noise pulses as
part of the program and either
banb or result in a garbled
conversion.
The FIRSTLOADER version has
the advantage of keeping the
machine language conversion
program in memory after the
conversion is complete. If the
user uses the DELETE command
to erase the program and CLEAR
to clear the variables ,
FIRSTLOADER can be called
again with the U5R ccmand to
convert the next program. NEW
will however, destroy
FIRSTLOADER.
Converted programs will
have any inverse characters
converted to normal upper-case
characters. Line numbers with
nothing after them usually
signify cawnands or functions
not in the 2068 vocabulary
such as SLOW, FAST, PLOT
(different on the 2068),
UNPL0T, SCROLL and Shift "Q"
("") and must be edited
accordingly . The numbers
following canmands or
functions such as CHR$, CODE,
PEEK, POKE, PLOT and USR must
be changed or re-formatted to
operate properly.
The FIRSTLOADER version we
used was typed in from the
SYNTAX issue and occupies
about 1/2 K of upper memory.
It worked every time with the
1000 programs we converted ,
but keep in mind, we have
equipment that can make very
clean copies.
Using this program may mean
a lot of time-saving cn your
part for those favorite
7
programs you were going to sit
down and type in fran
scratch .
1000 HI -RES
We saw a demonstration of
hi -resolution graphics on the
TS-1000 and were amazed.
Without any hardware changes,
either the SW-HI-RES program
($20.00) or the HI -RES WORD
PROCESSOR ($24.95) can be
loaded fran cassette tape .
Screen resolution is 174 by
255 pixels.
intact. The BASIC program that
a bunch of
machine-language sub-routines,
can be broken at any time. The
screen, however, will not
revert back to normal unless
the proper USR canmand is
executed . When another user
command is used, the Hi -Res
picture instantly returns.
The program seens to use
two areas of memory to map the
screen and the USR calls allow
you to toggle back and forth.
Whichever one is used , the
other is completely eliminated
from the screen.
New commands with the
SW-HI-RES program include
PLOT, UNPL0T, PRINT, PRINTC,
DRAW, CLS, 9CROL-UP, DOWN,
LEFT, RIGHT & COPY. Print-out
to the 2040 printer is
possible. You can create your
own character set and it canes
with a sample graphics
generator - that plots a
hi -resolution picture of
circles and sine waves to the
screen.
The only drawback we could
see was that the graphics
generation took a considerable
amount of time, however,
pictures could be saved on
tape and recalled instantly
when loaded.
The High resolution
graphics are generated to the
top 22 lines of the screen
with the bo t. tan two lines left
For further information ,
contact N. ELMALEH, 5100
HIGHBRIDGE STREET 53 ,
FAYETTEVILLE, NY, 13066
. . 8
SIMULATING DRAW & CIRCLE
CM THE TS-10Q0
Good morning , Class !
Today's session will be on
screen graphics for the
TS-1000.
Unlike the TS-2068, the
1000 does not have commands
such as DRAW and CIRCLE. These
contends can be simulated with
routines, however, the hi -res
graphics will be missing.
To simulate the DRAW
contend, enter the following
program:
10 LET X=0
20 LET Y=X
100 INPUT XX
110 INPUT YY
120 LET A=X-XX
130 LET B=Y-YY
140 LET C=( A AND ABS A>=ABS
B)
+ (B AND ABS B>ABS A)
150 IF C=0 THEN LET 0.1
160 FOR N=0 TO C STEP SO) C
170 PLOT X+A/C*-N ,Y+B/C*-N
1 180 NEXT N
. 190 LETT X=X+A/C*-N
' 200 LET Y=Y+B/C*-N
210 GOTO 100
This routine starts the
first plotted point at the
lower left hand of the screen
and is determined by the "X"
and "Y" values in lines 10 and
20, These of course can be
changed.
The inputs fran lines 100
and 110 ask for the pixel
position that the line is to
be drawn to. The first input
would be hew many pixels fran
the left border (1 to 62) and
the next input is for how many
pixels fran the bottom (1 to
42). Enter "20 ■ and "10" for
these inputs and a diagonal
line will be plotted and the
routine will recycle for the
next inputs.
Now enter two new screen
co-ordinates and a new line
will be drawn fran the last
plotted pixel to the new
destination . The starting
pixel position of the new line
is determined by lines 190 and
200 which reset the X/Y
values.
Line 140 does all the hard
mathematics and the program
uses various trig functions
which perform quite quickly
canpared to other IF/THEN
canpariscn techniques that are
ccrmon ly used.
Unlike the TS-2068 version
of DRW, this routine simply
asks for the screen positions
that the line is going to be
plotted to and draws the line
9
to that position fran the end
of the last line. With this
method you will not
accidentally draw a line off
the screen where an error
message will occur as long as
you stay within the specified
parameters .
By changing the following
lines to read:
190 INPUT X
200 INPUT Y
you can start the new lines at
any position you want.
But so much for straight
lines (almost straight). What
about curved lines , circles
and ellipses? Biter the
following simple program:
10 INPUT A
20 INPUT B
100 FOR 1=0 TO 2*PI STEP
PI/30
110 PLOT 30+A*006 I,B+fi*SIN I
120 NEXT I
Line 10 inputs the width of
the ellipsoid and line 20
inputs the height. If the two
inputs are the same, a circle
will result.
Now, what about curves? If
we look at line 100 we see the
segment "2*PI" . This
represents the circumference
of the circle or ellipscftd. If
the "2*" were missing, only
half of the circle or
ellipsoid would be plotted. If
you wanted only a fraction of
the ellipsoid to appear, add
and change the following
lines:
30 INPUT C
100 FOR 1=0 TO 2*PI*C STEP
PI/30
The variable "C” would
determine the fraction of
ellipsoid to be plotted
would be altered with line
with an input between .1
1 .
Class dismissed!
Of the Earth's
196,949,970 square
miles of area, 48 million
square miles of its
surface are always snow-
covered.
According to Figgie
International^ Ther-
mometer Corporation of
America (TCA), it takes
more than 1,000,000 ice
crystals to cover two
square feet with 10
inches of snow.
10
different.
Certain machine language
programs, including cnes fran
Synchro-Set te , will not run on
my ZX-81 resulting in an error
message - yet, when I put the
same tape into try friend's
TS-1000, it runs with no
problem.
We have checked the
listings and they appear
identical . We switched
Repacks (mine is a BYTE -BACK
16K and his is the Timex 16K)
and the problem seems to
follow the BYTE -BACK RAMpack.
Is my RAMpack faulty? Other
programs seem to run with no
trouble .
J. Thomas - Lincoln, NE
Dear Jerry,
The explanation we got was
that on the earlier BYTE-BACK
RAMpack s , certain RAM memory
locations conflict USR call
functions where-ipon the
design of the TS RAMpack is
Users have been telling us
that non -Timex RAMpacks will
not operate on the TS-1500
either, with a variety of
malfunctions - Ed.
Dear Ed,
Does the S & S Company have
any future plans regarding any
kind of subscription computer
publications?
L. Peaslee - Bronx, NY
Dear Len,
Not at this time. One of
the big problems regarding
Synchro-Sette is the lack of
material to put into the
magazine . Programs can be
written cn almost every
conceivable subject but
newsworthy topics are becoming
harder to cane by . Sane
catpanies that supplied
software, hardware and news
information which were viable
a few months ago are no longer
in business now.
On the other side of the
coin, the purchasing customers
of Timex equipment have
dwindled to the point where
many of the supporting
canpanies feel the odds are
against them to advertise
11
their wares in any
publication .
Perhaps the TIME-STAR
program (see Editor Ramblings
This issue) will turn this
around . I think most
supporting companies have
developed a "wait and see"
attitude before they rrake any
caimitments .
We will continue to support
the Timex computers as long as
there is a market - Ed.
Dear Ed,
I purchased a IS- 20 68 from
Timex at the close-out price
of $99.95 and an wry
impressed with it . I was
particularly impressed with
your "SPIDERS" program in the
January 1984 issue. I wish the
volume of the sound output
could be increased and there
was a 80 column output
device.
But for 100 bucks, this is
the best deal going! I'm sad
to see your publication phase
out. I realize the number of
subscribers aren 't there
anymore but I have learned a
great deal fran your magazine
and cassette programs and will
stay with you to the end .
Thanks again.
S. Greenstein - Colorado
Springs, 00
Dear Sherwin,
We are also saddened at the
outcome, but who knows what
the future will hold - Ed.
m
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7mm
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777777777777777777717777717
Which country is setting
records for production by
its dairy cows, even though
that country is one of the
smallest in the world?
Although most people
expect cows to thrive on a
diet of water, grass and
grain, this country's cattle
have learned to love a com-
puter-prepared menu of to-
mato pulp, orange peels,
silage and residues from
beer and cheese production.
Statistics show they’re thriv-
ing and so is milk produc-
tion. Can you name the
country?
ANSWER: The country
is Israel. Thanks to comput-
erized genetic planning, its
cows have helped that coun-
try achieve the highest milk
production in the world.
Since water, grass and grain
are three items lacking in
that arid land, its scientists
have come up with a diet
that seems to work won-
ders. The country’s dairy
farmers say they still have
much to 1 earn from Ameri-
can farmers but report that
one of their success secrets
is the fact that ALL of their
dairies are high producers.
12
A SCREEN MEMORY MAPI
FOR THE 1S-3.068 J
Cn the TS-1000 we learned
that the screen could be
addressed directly by PCKEing
numeric values directly into
certain memory locations. The
locations that were to be
PQKEd depended cn how much
memory the program in the
canputer took xp. The memory
locations for the screen
resided in an area above the
program memory and was said to
"float”. The first screen
location could be determined
with the formula "LET X = PEEK
16396 + 256 * PEEK 16397 +
1 ".
We also learned that the
screen was stored in memory as
24 lines of 33 characters each
for a total of 792 memory
locations. The first 32
characters of each line cn the
screen would have their CODE
numbers held in memory and
could be changed by PCKEing
that memory location with a
different number.
The last row or character
should not be PCKEd because it
held a value of 118 which,
when altered, would cause the
program to crash.
Try as I may, I could not
find an area in the TS-2068 's
memory that held the CODE
numbers of the characters on
the screen.
There is a good reason for
this! None of the techniques
used to hold screen
information for the 1000 are
used in the 2068, as far as 1
can see!
The CODE numbers of the
screen characters are not held
in memory but exact screen
information is retained in
memory in a very devious and
complicated way.
On page 265 of the owner's
manual we find that the screen
DISPLAY FILE resides in the
memory locations between
400Q-57FF hex or 16384 to
22527 decimal. Unlike the
1000, whose screen memory nap
floats, the 2068 's screen map
resides in a stationary area.
This should make it easy to
address , right? Read cn
One day, while trying to
POKE these locations with
character CCDEs , I discovered
I was winding up with seme
weird arrangement of dots
ranging fran cne dot to a line
of 8 dots.
The answer was obvious! The
characters cn the screen were
13
not being held in memory by
their individual OODE numbers
but with a total of 8 numbers
for each character . Each
character was represented by
an 8 by 8 matrix where each
line was represented by the
visual represen tat ion of an 8
digit binary number. The
letter "A" would therefore be
seen as;
0000 0000
00111100
01000010
01000010
01111110
01000010
01000010
00000000
(0)
(60)
( 66 )
(66)
(126)
(66)
(66)
( 0 )
The 0s and Is on the left
side are the binary numbers of
the letter "A" where the 0's
are visually displayed on the
screen as "null" or blank dots
(PAPER colour) and the Is are
displayed as solid dots (INK
colour). The numbers to the
right of the binary numbers
are their decimal equivalent
and it is these that are
stored in memory . In other
words , it takes 8 numbers,
stored in memory, to hold the
information for each screen
character . The amount of
screen locations are 32
characters per line (not 33 as
on the 1000) for 24 lines for
a total of 768 positions. 8
decimal BIN numbers are in
memory for each screen
character for a total of 6144
RAM memory locations (6K) to
hold the entire screen map.
Now comes the complicated
part! The screen is divided
into 3 sections of eight lines
each. The top third section
resides in RAM at locations
16384 to 18431, the middle
third at locations 18432 to
20479 and the bottom third at
locations 20480 to 22527. The
locations for the lines of
bit-graphics for each
character are not consecutive
as can be demonstrated by the
following program:
100 FOR N=16384 TO 22527
110 PCKE N,1
120 PRINT AT 21,20;N
130 NEXT N
This routine PCKEs a single
dot to the screen at every
possible bit-graphics (BIN)
location . You will notice that
the screen is scanned in 3
sections with each section
being scanned 8 times . The
following routine produces a
screen grid (bottom 2 lines
not in grid) for easy
visualization and asks the
user for 2 inputs. The first
is the character you want to
be POKED from the screen and
the second is a co-ordinate.
Enter either an alphabetic,
numeric or graphic character
for the first pranpt. For the
second pranpt the following
parameters must be observed:
TOP THIRD OF SCREEN - 0 TO
255
14
(continued on back page)
The TS-2068 has sane unique
graphics capabilities as most
users already know. PLOT
allows Hi -Res plotting of any
screen pixel. DRAW allows
straight lines (as nearly as
the computer can make them)
between the last plotted pixel
to the new co-ordinates.
CIRCLE makes a circle with a
slight eliptical shape.
There is no catmand to draw
elipsoids directly or for that
matter, a more perfect circle.
The DRAW canmand, however, can
also draw circles or parts of
circles. A pixel has to be
plotted on the screen first
that would be far enough a way
fran the borders so that the
DRAW routine does not run out
of roan.
DRAW followed by 2 numbers,
separated by a comma, normally
plots a straight line to the
co-ordinates of the 2 numbers.
If a caima and third number
follow, a curved line will
result. The straight line
distance between the two
points is still the same as if
cnly 2 numbers were used but
the curve will occur between
the points . Biter the
following program;
100 INPUT A,B
110 CLS
120 PLOT 50,50
130 DRAW A,B
140 PAUSE 40000
150 CLS
160 PLOT 50,50
170 DRAW A,B,PI
180 PAXE 40000
190 CLS
200 PLOT 50,50
210 DRAW A, B, PI/2
220 GOTO 100
Experiment with inputs such
as 50,50 and 30,60 etc. You
will notice the slope of the
curve changes each Hire in
proportion to the value of the
third number. Edit lire. 170 to
read:
170 DRAW A,B,PI * x
where "x" equals a number
in between .1 and 1.65. You
new have an indication of how
this third number affects the
curve.
The CIRCLE ccmnand cannot
draw a perfect circle but a
routine can be written that
can draw a circle as perfect
as the computer is capable. It
can also draw elipsoids.
The following program will
draw a pretty good ellipse
with only 9 program lines.
15
10 INPOT "Length? " ; 1 : LET
C=1
20 INPOT "Height? ";h: IF H<C
THEN LET c=h
30 CLS : LET b=l/(l4h): LET a
= h/tl+h)
40 PLOT c,c
50 DRW l,0,PI*a
60 DRW 0,h,PI*b
70 DRAW -l,0,PI*a
80 DRAW Q,-h,PI*b
90 GOTO 10
The length input will be an
approximation of the length
fran left to right and the
height fran qp to dawn.
The program actually plots
the elipsoids as 4 parts, each
the part of a circle
determined as a fraction of
its circimfrence by lines 50
to 80.
The variable "c" in lines
10 and 20 determines the
starting PLOT positions in
line 40 so that the greatest
amount of elipsoids can be
tested.
The Variables "a" and "b"
determined by line 30 and used
in lines 50 determine the
portion of the circle to be
used in each of the 4 elipsoid
segments which line ip
perfectly to give as true an
elipse as can be expected.
Ranove the CLS carmand in line
30 to get an overlay cn your
screen .
If the length is 25%
greater than the height , a
near perfect circle will be
drawn such as if length = 50
and height = 40.
Print-out to the 2040
printer, however, still shows
sane elongation upwards so
experimentation is needed to
get the correct results. This
is a useful routine wherever
screen graphics requiring
circles or elipsoids are
needed such as drawings , games
or business charts - Ed.
(SCREEN CONTINUED )
MIDDLE THIRD - 2048 TO
2303
BOTTCM THIRD - 4096 TO
4351
The character you alter for
the first prompt will appear
in the upper left hand comer
of the screen . The second
pranpt must have a number
entered that fits into the
range above. The character
will then be POKED to the new
screen location, byte by
byte.
This routine nay help you
write a program in which you
can create your .awn hi -res
screen graphics to cover the
entire screen. All you have to
do is determine the. BINARY
image of each graphic
character you want to appear,
convert the binary numbers
into decimal and POKE than
into the proper memory
locations - Ed.